Why Do Chemical Weapons Evoke Such A Strong Reaction?

It took more than two years and at least 100,000 lives lost for the U.S. government to threaten Syria with military action. The catalyst was the Syrian military's alleged use of chemical weapons. President Obama called the attack on August 21st an assault on human dignity.

JACKIE NORTHAM, BYLINE: There has been no shortage of bloodshed, massacres, and misery coming out of Syria since the uprising against Bashar al-Assad's regime began in 2011. But the chemical weapons attack on August 21st - which the Obama administration says killed nearly 1,500 men, women, and children - crossed a line. Secretary of State John Kerry and President Obama have given impassioned speeches about the horror of chemical weapons and how the U.S. should address the attack.

SECRETARY JOHN KERRY: We saw rows of children lying side-by-side sprawled on a hospital floor, all of them dead from Assad's gas and surrounded by parents and grandparents who had suffered the same fate.

PRESIDENT BARACK OBAMA: What message will we send if a dictator can gas hundreds of children to death in plain sight and pay no price?

NORTHAM: The victims of that attack represent just a fraction of the total number of people killed in the Syrian conflict so far. But Gregory Koblentz, with the bio-defense program at George Mason University, says the use of chemical weapons has a visceral effect on many people.

GREGORY KOBLENTZ: Chemical weapons are part of a class of risk called dreaded risk. These are kinds of hazards that people have a disproportionate, psychological response to in terms of fear, anxiety, disgust.

NORTHAM: Jeffrey Lewis, with the Monterey Institute of International Studies, says when you think about the worst weapons out there, chemical weapons seem to meet all the criteria.

JEFFREY LEWIS: It's a particularly terrible way to die. And if you don't die, you will have very long-term health problems. They are indiscriminate; you can't use them on a battlefield in a way that doesn't harm civilians. And they enable killing on a very large scale. Now, killing 1,500 people in a span of a few hours is really awful.

NORTHAM: Chemical weapons were actually banned before they were ever invented. That was back in 1899 when negotiators at an international peace conference in The Hague saw the devastating potential of chemicals, such as chlorine. Despite that, chemical weapons - including chlorine - were widely used during World War I, says Koblentz.

KOBLENTZ: And even though the number of deaths and fatalities that chemical weapons caused in World War I were a fraction of the, you know, overall mayhem that that conflict wreaked on Europe, chemical weapons emerged as one of the symbols of a, you know, an inhumane weapon.

NORTHAM: It was the widespread use during World War I that led directly to the 1925 Geneva Convention, which outlawed chemical and biological weapons. That was later beefed-up with the 1992 Chemical Weapons Convention. But there are other equally terrible ways to die in an armed conflict and many people question why the U.S. should respond so strongly to one chemical weapons attack in Syria and not to other atrocities committed in that conflict.

RICHARD PRICE: Why of all the horrible things that happen in warfare have chemical weapons been singled out?

NORTHAM: Richard Price is a professor of political science at the University of British Columbia and the author of the book "The Chemical Weapons Taboo." He says anxiety many people feel about chemical weapons stems from more than just fear and revulsion. Price says unlike other weapons, they've only been used a handful of times, there's a prohibition against them, and a long history of political efforts to restrain their use.

PRICE: And the best way to appreciate that is the way that we have this term that we use all the time - conventional weapons, right. And that very notion seems to help legitimize that, well, this is OK. It's OK to get, you know, blown up to death or burned to death.

NORTHAM: Price says the prohibition and effort to contain chemical weapons show that humanity can control weapons when it sets its mind to it.